<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    .title1{
      color: red;
    }
    .title2{
      color: blue;
    }
  </style>
</head>
<body>

<h1 class="title1">标题1</h1>
<h1 class="title2">标题2</h1>
<h1 class="title1">标题3</h1>

<p class="title1">p标签</p>
</body>
</html>